In a telephone system where multiple phones are connected to one telephone line, if someone is talking on one of the phones, another party can pick up a second phone and eavesdrop on the conversation. Likewise, if a fax machine or computer is transmitting information on a telephone line and someone picks up a phone connected to the same line, the fax or computer transmission can be interrupted.
Various devices have been proposed for solving this problem; however, the existing devices have various technical or cost disadvantages. For example U.S. Pat. No. 3,499,121 (Mcintosh) describes devices which can provide privacy; however, the devices described in the Mcintosh patent have a relatively large number of components and they are therefore costly. U.S. Pat. No. 4,726,048 (Waldman) shows a different type of device for providing privacy in a telephone system. The device shown in the Waldman patent only needs to be connected to one phone in a system and the phone to which the device is connected in effect become a master phone. If someone initiates a call on the master phone and at a later time someone picks up one of the extension phones, the person who initiated the call will be cut off and only the person using the extension phone will have access to the line.
The present invention provides a telephone privacy or exclusion device which does not have the disadvantages of the prior art privacy or exclusion devices.